Renewable heating for conservatory

Q. I would like to use renewable energy to heat my conservatory. But I have looked into solar, wind and ground heating types of systems, and I seem to have drawn blanks. I contacted the local authority building engineer and was informed that I needed to contact a renewable energy help-line, which still seemed limited regarding information. Can you recommend the best type of heating that would suit a conservatory, renewable if possible? I am quite surprised at the lack of information and potential uses for renewable energy.

A. If you want to be “green” in your approach (which I guess you do, from your references to renewable energy) then the best thing would be to not heat your conservatory at all. To keep a standard double- glazed 30 sq m conservatory at a “habitable” temperature in winter would mean pumping heat into it at a rate of around 3 to 5 kW, and all that energy will quickly find its way out through the glass roof and windows. There has been a lot of publicity recently about solar and wind power, but an affordable domestic solar or wind installation will produce only a small amount of energy – enough for a few electric lights, or to pre-heat the hot-water supply, but nowhere near enough for space heating. Ground-source heat pump systems cost upwards of £10,000 to install, which might mean a pay-back period of 50 to 60 years. They are also likely to use more energy in their manufacture and installation than they will produce over that period, so they are not necessarily “renewable” themselves. There is a high level of misunderstanding about the renewable energy issue, which is not helped by propaganda from various government departments